Back frame

ABSTRACT

A back frame that includes a first part and a second separate part configured to disengagingly interlock at plural relative positions to define respective assembled configurations of the back frame of two or more distinct lengths, whereby the back frame is adjustable for wearers of different heights. The interlocking includes releasably interengaging the first and second parts by relatively moving the first and second parts in a first direction generally toward each other and then in a second direction generally perpendicular to the first direction.

FIELD OF THE INVENTION

The present invention relates to back frames suitable for attachment to a backpack, rucksack, or similar.

BACKGROUND OF THE INVENTION

External back frames (also known as pack frames or backpack frames) are typically utilised when a wearer is required to carry heavy loads upon his or her back. In one example, external back frames are worn by military or combat personnel. Such external back frames provide greater support, weight distribution, and wearer protection as compared to frameless backpacks or backpacks comprising an internal back frame.

U.S. Pat. No. 7,793,809 describes an external back frame that is particularly suited to military application. This back frame comprises a one-piece unit having a pair of spaced generally parallel vertical side rails that are joined by generally parallel top and base cross-structures. This back frame is sized and dimensioned so as to be suitable for a wearer of a particular height.

It is an object of the present invention to provide a back frame that overcomes, or at least ameliorates, one or more deficiencies of prior back frames, or at least provides a useful alternative.

Reference to any prior art in the specification is not an acknowledgment or suggestion that this prior art forms part of the common general knowledge in any jurisdiction or that this prior art could reasonably be expected to be understood, regarded as relevant, and/or combined with other pieces of prior art by a skilled person in the art.

SUMMARY OF THE INVENTION

In a first aspect, the invention provides a back frame that includes a first part and a second separate part configured to disengagingly interlock at plural relative positions to define respective assembled configurations of the back frame of two or more distinct lengths, whereby the back frame is adjustable for wearers of different heights. The interlocking includes releasably interengaging the first and second parts by relatively moving the first and second parts in a first direction generally toward each other and then in a second direction generally perpendicular to the first direction.

The relative movement of the first and second parts in the second direction may comprise the first and second parts sliding over each other.

In an embodiment, the back frame includes one or more first formations on one of the first and second parts and a plurality of second formations on the other of the first and second parts, the or each first formation selectively engaging the respective second formations to define the respective assembled configurations of the back frame when the first and second parts are releasably interengaged.

The first and second formations may be disengaged by relatively moving the first and second parts in a direction opposite to the second direction and then in a direction opposite to the first direction. The first and second parts of the back frame may be wholly separable when the first and second formations are disengaged.

The first formation may comprise a projecting locking formation and the second formations may comprise apertures, wherein when the first and second parts are relatively moved in the first direction the projecting locking formation is received in a selected opposed aperture. The apertures may be generally rectangular or rhomboid in shape, and are preferably dimensioned to receive the locking formation.

The first part of the back frame may include a locking formation and the second part of the back frame then includes a plurality of the opposed apertures. Furthermore, the second part of the back frame may then include a locking formation and the first part of the back frame may include a further plurality of apertures.

In an embodiment, the or each locking formation comprises a generally L-shaped projection which slidingly engages a peripheral wall of the respective opposed aperture so as to be releasably wedged therein. The or each L-shaped projection may be adapted to slidingly engage the peripheral wall of the respective opposed aperture by relatively sliding the first and second parts of the back frame over each other in the second direction.

Preferably, there are four of the locking formations arranged in a rectangular array, which is advantageous for rigidity in the respective assembled configurations.

The first and second parts may each include a pair of spaced generally parallel side rails and one or more spaced cross-structures joining the side rails, wherein each side rail has therethrough a plurality of the aforesaid apertures arranged in a linear array along the respective side rail.

The first and second parts are preferably substantially symmetrical about a vertical centreline parallel to the side rails.

In an embodiment, one of the one or more spaced cross-structures has, integrally formed therewith at a position between the side rails, a lumbar support member that projects without further support from the one cross-structure so as to be inclined to a plane, optionally curved, containing the side rails.

The back frame may further include a releasable latch arrangement that must be released e.g. by hand, in a first action to allow disengagement of the first and second parts from interlocking engagement. The latch arrangement may comprise one or more further locking formations located on one of the frame parts which further locking formation is receivable within plural said apertures of the other part and when therein abuts a peripheral wall of the respective aperture when the first and second parts are interengaged thereby preventing relative sliding between the first and second parts, and thereby interlocking the first and second parts.

In an embodiment, the or each further locking formation is provided on a respective tab configured to be resiliently flexed e.g. by finger pressure, in said first action.

There may be a pair of the latch arrangements at respective sides of the back frame.

The lumbar support member and the one cross-structure are dimensioned so that the lumbar support member contacts a lumbar region of the wearer's back when the back frame is being worn, and are preferably configured so that the lumbar support member is able to elastically flex during such contact.

In a preferred embodiment, the first and second parts are curved so as to follow or approximate a typical curvature of a wearer's back.

In a preferred embodiment, the first part and/or the second part include one or more first attachment points such that the back frame may be releasably attached to a backpack, rucksack, or the like. Preferably, the first part and/or the second part further include one or more second attachment points that are dimensioned to receive straps, such as hip, waist, or shoulder straps.

Preferably, the first and second parts are dimensioned such that the back frame is adjustable to vary its length by up to, 150 mm, for example, up to 120 mm.

Preferably, the first and second parts are respective unitary single mouldings.

In a second aspect, the present invention provides a back frame comprising:

a pair of spaced generally parallel side rails that define a plane, optionally curved, containing the side rails; and

one or more spaced cross-structures joining the side rails, wherein said one cross-structure has, integrally formed therewith at a position between the side rails, a lumbar support member that projects without further support from the one cross-structure so as to be inclined to said plane;

wherein the lumbar support member and the one cross-structure are dimensioned so that the lumbar support member contacts a lumbar region of a wearer's back when the back frame is being worn, and are configured so that the lumbar support member is able to elastically flex during said contact.

Preferably, the lumbar support member is generally of inverted U-shape.

Preferably, the lumbar support member is upstanding from said one cross-structure when the backpack is worn in the correct orientation.

As used herein, except where the context requires otherwise, the term “comprise” and variations of the term, such as “comprising”, “comprises” and “comprised”, are not intended to exclude further additives, components, integers or steps.

Further aspects of the present invention and further embodiments of the aspects described in the preceding paragraphs will become apparent from the following description, given by way of example and with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front perspective view of a back frame according to an embodiment of the invention;

FIG. 2A is a front view of a first, lower, part of the back frame of FIG. 1, constituting a base frame;

FIG. 2B is a front view of second, separate and upper, part of the back frame of FIG. 1, constituting a top frame;

FIG. 3A is respectively a front elevation and a partial cross-sectional view, on the line A-A, of the first and second separate parts of the back frame of FIG. 1 in a fully disengaged or unassembled configuration;

FIG. 3B comprises views similar to those of FIG. 3A but with the back frame parts in a partially engaged configuration or partially assembled configuration;

FIG. 3C compares views similar to those of FIG. 3A but with the back frame parts in a fully engaged or assembled configuration; and

FIG. 4 is a close-up fragmentary perspective view of the back frame of FIG. 1, which view includes a latch mechanism.

In the figures, the “front view” illustrates a front side of the back frame (or a front side of the first and second separate parts). When in use, the front side faces the wearer's back. When mentioned herein, a “rear view” is of a rear side of the back frame (or a rear side of the first and second separate parts). When in use, the rear side faces a backpack or other item carried by the back frame.

DETAILED DESCRIPTION OF EMBODIMENTS

Referring to FIG. 1, there is shown a back frame 10 for a backpack or the like that comprises a first part in the form of a generally rectangular base frame 12, and a second separate part in the form of generally rectangular top frame 14. The base frame 12 and the top frame 14 are transversely and longitudinally curved, or are generally concave, so as to follow or approximate a typical curvature of a wearer's back. The base frame 12 and the top frame 14 disengagingly interlock at plural relative positions to define respective assembled configurations of the back frame 10 of two or more distinct lengths (a first length being illustrated in FIG. 1). In this manner, as described in further detail below, the back frame 10 is adjustable for wearers of different heights.

The base and top frames 12, 14 each include a pair of respective spaced generally parallel vertical side rails 16, 18 that are joined by respective generally transversely extending cross-structures 20, 22. As illustrated in the figures, the base and top frames 12, 14 are each symmetrical about a vertical centreline extending through each frame. Each of base and top frames 12, 14 is a unitary single moulding in a suitable high strength plastic material eg a polycarbonate. The frames are preferably rigid but may exhibit some flexure under prescribed loads.

The base and top frames 12, 14 disengagingly interlock by means of complementary locking formations and apertures located on each frame.

Projecting generally forwardly from the upper ends of side rails 16 of the base frame 12 are a pair of first formations in the form of projecting locking formations that comprise generally inverted L-shaped projections 24 (see FIG. 2A). The projections 24 are generally inverted L-shaped when viewed in cross-section and are generally rectangular when viewed front-on. In an assembled configuration of the back frame 10 (see FIG. 1), the first pair of L-shaped locking projections 24 of the base frame 12 are releasably received in a respective pair of a plurality of second formations in the form of generally rectangular or rhomboid-shaped apertures 30 in side rails 18 of the top frame 14. Each side rail 18 has a linear array of equispaced apertures 30.

Similarly, projecting generally rearwardly from a lower end of each side rail 18 of the top frame 14 are a second pair of locking formations 28 similar in form to projections 24 (see FIG. 2B). In the assembled configuration, the second pair of L-shaped locking projections 28 of the top frame 14 are releasably received in a respective pair of a plurality of similar vertically arrayed generally rectangular or rhomboid-shaped apertures 26 that are equi-spaced-apart along each side rail 16 of the base frame 12 (see FIG. 2A). As illustrated in FIGS. 2A and 2B, the first pair of L-shaped projections 24 project in an opposite direction to the second pair of L-shaped projections 28, such that the L-shaped projections 24, 28 releasably wedge within a respective opposite aperture in an assembled configuration, as is described below.

Advantageously, when the first and second pairs of L-shaped locking projections 24, 28 are interengaged with the respective opposed apertures 30, 26, the base and top frames 12, 14 are firmly interlocked at all four positions. The base and top frames 12, 14 are particularly rigidly interlocked due to the arrangement of the four L-shaped locking projections 24, 28 being on opposite side rails 16, 18 of the base and top frames 12, 14 respectively.

The interengagement between the base and top frames 12, 14 to form the assembled back frame 10 will now be described with reference to FIGS. 3A to 3C. FIG. 3A illustrates the base and top frames 12, 14 overlapping in close proximity but in a fully disengaged or unassembled configuration. As can be particularly seen in the cross-sectional view of FIG. 3A, the first L-shaped locking projection 24 of the base frame 12 (shown in hatched lines) is located adjacent to, but removed from, the opposing aperture 30 of the top frame 14 (shown in cross-hatched lines). Similarly, the second L-shaped locking projection 28 of the top frame 14 is located adjacent to, but removed from, the opposing aperture 26 of the base frame 12. In this position, the top and base frames 12, 14 are fully disengaged or separate, but may be partially engaged by pushing each frame 12, 14 generally inwardly (or together) as illustrated by the arrows 102 in FIG. 3A.

Referring now particularly to the cross-sectional view illustrated in FIG. 3B, the first L-shaped locking projection 24 of the base frame 12 is now received within, or located within, the opposing aperture 30 of the top frame 14. Similarly, the second L-shaped locking projection 26 of the top frame 14 is now received within the opposing aperture 28 of the base frame 12. In this position, the top and base frames 12, 14 are partially engaged or partially assembled, but may be fully engaged or fully assembled by sliding each frame 12, 14 in generally opposite directions parallel to side rails 16, 18 (as indicated by the vertical arrows 104 in FIG. 3B).

Referring now particularly to the cross-sectional view illustrated in FIG. 3C, the first L-shaped locking projection 24 of the base frame 12 has slidingly engaged orthogonal peripheral walls 30 a of the opposed aperture 30 of the top frame 14. Similarly, the second L-shaped locking projection 28 of the top frame 14 has slidingly engaged orthogonal peripheral walls 26 a of the opposed aperture 26 of the base frame 12. In this sense, the L-shaped projections 24, 28 are releasably wedged within the opposed apertures 30, 26 (or against the peripheral walls 30 a, 26 a thereof). The base and top frames 12, 14 are now fully interengaged such that the back frame 10 is now fully assembled at one of the plural relative positions.

The base and top frames 12, 14 are disengagingly interlocked in this position by a latch arrangement comprising a pair of similar latches 100 symmetrically arranged at opposite sides of the assembly when viewed from the rear or front. Each latch 100 comprises an angled elongate planar tab 50 cut from within an enlarged upper end portion 17 of a respective rail 16 of base frame 12 so that the tab remains attached at its inner vertical edge 51 (FIG. 2A), whereby the tab is hinged at this edge and able to be resiliently flexed from its rest position flush with end portion 17. The inner end of tab 50 near the hinge edge has an integral L-shaped internal land or projection 40 that, when the base and top frames are in their fully interengaged assembled condition as described above, engages two edges of an aperture 30 of the rail 18 of the top frame 14. By doing this the L-shaped lands or projections 40 lock the rail pairs, and therefore the frame, together by preventing inadvertent relative sliding of the rail pairs that might release the engagements between projections 24, 28 and apertures 26, 30. Such inadvertent disengagement is a risk in the field, especially with heavily loaded packs in challenging conditions.

Lands or projections 40 can be unlatched from aperture 30 by resiliently pressing the free ends 52 of tabs 50 in the direction of the arrow “PRESS” in FIG. 4. This is the first step of a three action movement required to disengage the base and top frame for adjusting the length of the back frame.

Thereafter, the base and top frames 12, 14 may be slid longitudinally and parallel to side rails 16, 18 with respect to each other back to the partially engaged position illustrated in FIG. 3B. In this position, the base and top frames 12, 14 can then be separated by pulling each frame generally away from one another (or at least one of the frames away from the other)—the base and top frames 12, 14 have now returned to the fully disengaged position illustrated in FIG. 3A.

It will be appreciated that the position of the L-shaped locking projections 24, 28 within the respective opposed apertures 30, 28 defines the overall length (or height) of back frame 10. For example, if the L-shaped locking projections 24 of the base frame 12 were located within the lowermost opposed apertures 30 of the top frame 14, the back frame 10 will be at its maximum length. However, if the L-shaped locking projections 24 of the base frame 12 were located within the uppermost opposed apertures 30 of the top frame 14, the back frame 10 will be at its minimum length. The back frame 10 is designed such that the difference between its maximum and minimum lengths, ie the range over which the back frame is adjustable, is 120 mm, represented by five 30 mm increments. In general, this difference, or adjustment range, may be up to 150 mm. For the Australian population, the variation in back length 1 percentile female to 99 percentile male is 153 mm: an adjustment range of 120 mm is thought acceptable to cover this 98% of the population group.

Certain other features of the illustrated back frame 10 will now be described. Referring particularly to FIGS. 1 and 2A, the base frame 12 includes a generally inverted U-shaped lumbar support member 60 integrally formed with a lowermost transversely extending cross-structure 20. The U-shaped lumbar support member 60 projects without further support from the lowermost cross-structure 20 so as to be inclined to a plane containing the side rails 16. The U-shaped lumbar support member 60 and the lowermost cross-structure 20 are dimensioned such that the lumbar support member 60 contacts a lumbar region of a wearer's back when the back frame 10 is worn (not shown). Advantageously, the U-shaped lumbar support member 60 exhibits a resilient hinging action such that it is able to elastically flex during such contact, thereby providing responsive support to the lumbar region of the wearer's back. The back frame 10 comprises a moulded material, such as a suitable polycarbonate, that is able to elastically deform.

The base and top frames 12, 14 further include a plurality of generally elongate pill-shaped attachment slots 70 disposed on side and end structures or wings 71 of each frame. As illustrated in FIG. 2A, the base frame 12 includes symmetrically arranged elongate attachment slots 70 located about the hips of the wearer (when the back frame 10 is worn). Similarly, the top frame 14 includes symmetrically arranged attachment slots 70 located about the upper and side regions of the shoulders of the wearer (when the back frame is worn). The attachment slots 70 are utilised to releasably attach the back frame 10 to a suitable backpack, rucksack, or similar (not shown). The attachment slots 70 are also utilised to releasably receive one or more straps or belts, such as hip, waist, or shoulder straps (not shown). The configuration, shape and number of slots 70 and of side and end structures or wings 71, may of course vary according to the intended use of the back frame.

It will be understood that the invention disclosed and defined in this specification extends to all alternative combinations of two or more of the individual features mentioned or evident from the text or drawings. All of these different combinations constitute various alternative aspects of the invention. 

1. A back frame comprising: a first part and a second separate part configured to disengagingly interlock at plural relative positions to define respective assembled configurations of the back frame of two or more distinct lengths, whereby the back frame is adjustable for wearers of different heights; wherein said interlocking includes releasably interengaging the first and second parts by relatively moving the first and second parts in a first direction generally toward each other and then in a second direction generally perpendicular to the first direction,
 2. The back frame of claim 1 configured whereby said relative movement of the first and second parts in the second direction comprises the first and second parts sliding over each other.
 3. The back frame of claim 1, including one or more first formations on one of the first and second parts and a plurality of second formations on the other of the first and second parts, the or each first formation selectively engaging the respective second formations to define the respective assembled configurations of the back frame when the first and second parts are releasably interengaged.
 4. The back frame of claim 3, wherein the first and second formations are disengaged by relatively moving the first and second parts in a direction opposite to the second direction and then in a direction opposite to the first direction.
 5. The back frame of claim 3, wherein the first and second parts of the back frame are wholly separable when the first and second formations are disengaged.
 6. The back frame of claim 2, wherein the first formation comprises a projecting locking formation and the second formations comprise apertures, wherein when the first and second parts are relatively moved in the first direction the projecting locking formation is received in a selected opposed said aperture.
 7. The back frame of claim 6, wherein the first part of the back frame include a said locking formation and the second part of the back frame includes a said plurality of the opposed apertures.
 8. The back frame of claim 7, wherein, the second part of the back frame includes a said locking formation and the first part of the back frame includes a further said plurality of apertures.
 9. The back frame of claim 6, wherein the or each locking formation comprises a generally L-shaped projection which slidingly engages a peripheral wall of the respective opposed aperture so as to be releasably wedged therein.
 10. The back frame of claim 9, wherein the or each L-shaped projection is adapted to slidingly engage the peripheral wall of the respective opposed aperture by relatively sliding the first and second parts of the back frame over each other in said second direction.
 11. The back frame of claim 6, wherein there are four of said locking formations arranged in a rectangular array.
 12. The back frame of claim 11, wherein the first and second parts each include a pair of spaced generally parallel side rails and one or more spaced cross-structures joining the side rails, wherein each side rail has therethrough a plurality of said apertures arranged in a linear array along the respective side rail.
 13. The back frame of claim 12, wherein one of the one or more spaced cross-structures has, integrally formed therewith at a position between the side rails, a lumbar support member that projects without further support from the one cross-structure so as to be inclined to a plane, optionally curved, containing the side rails.
 14. The back frame of claim 1, further including a releasable latch arrangement that must be released in a first action to allow disengagement of the first and second parts from interlocking engagement.
 15. The back frame of claim 3, further including a releasable latch arrangement that must be released in a first action to allow disengagement of the first and second parts, wherein the latch arrangement comprises one or more further locking formations located on one of said parts which further locking formation is receivable within plural said apertures of the other part and when therein abuts a peripheral wall of the respective aperture when the first and second parts are interengaged thereby preventing relative sliding between the first and second parts, and thereby interlocking the first and second parts.
 16. The back frame of claim 15, wherein the or each further locking formation is provided on a respective tab configured to be resiliently flexed in said first action.
 17. The back frame of claim 15, including a pair of said latch arrangements at respective sides of the back frame.
 18. The back frame of claim 1, wherein the first and second parts are curved so as to follow or approximate a typical curvature of a wearer's back.
 19. The back frame of claim 1, wherein the first and second parts are respective unitary single mouldings.
 20. A back frame comprising: a pair of spaced generally parallel side rails that define a plane, optionally curved, containing the side rails; and one or more spaced cross-structures joining the side rails, wherein one of the one or more spaced cross-structures has, integrally formed therewith at a position between the side rails, a lumbar support member that projects without further support from the one cross-structure so as to be inclined to said plane; wherein the lumbar support member and the one cross-structure are dimensioned so that the lumbar support member contacts a lumbar region of a wearer's back when the back frame is being worn, and are configured so that the lumbar support member is able to elastically flex during said contact.
 21. The back frame of claim 20, wherein the lumbar support member is generally of inverted U-shape and is upstanding from the one cross-structure when the back frame is worn in a correct orientation.
 22. The back frame of claim 14, including a pair of said latch arrangements at respective sides of the back frame.
 23. The back frame of claim 10, wherein there are four of said locking formations arranged in a rectangular array.
 24. The back frame of claim 23, wherein the first and second parts each include a pair of spaced generally parallel side rails and one or more spaced cross-structures joining the side rails, wherein each side rail has therethrough a plurality of said apertures arranged in a linear array along the respective side rail. 